2013/07/09

Regulation of nuclear envelope dynamics that is necessary for the progression of semi-open mitosis

Microbial Genetics Laboratory • Niki Group

Regulation of nuclear envelope dynamics via APC/C is necessary for the progression of semi-open mitosis in Schizosaccharomyces japonicus
Keita Aoki, Yuh Shiwa, Hiraku Takada, Hirofumi Yoshikawa and Hironori Niki
Genes to Cells 21 JUN 2013 DOI: 10.1111/gtc.12072. [Epub ahead of print]

Three types of mitosis, which are open, closed, or semi-open mitosis, function in eukaryotic cells, respectively. The open mitosis involves breakage of the nuclear envelope before nuclear division, whereas the closed mitosis proceeds with an intact nuclear envelope. To understand the mechanism and significance of three types of mitotic division in eukaryotes, we investigated the process of semi-open mitosis, in which the nuclear envelope is only partially broken, in the fission yeast Schizosaccharomyces japonicus. In anaphase-promoting complex/cyclosome (APC/C) mutants of Sz. japonicus, the nuclear envelope remained relatively intact during anaphase, resulting in impaired semi-open mitosis. As a suppressor of apc2 mutant, a mutation of Oar2 which was a 3-oxoacyl-[acyl-carrier-protein] reductase was obtained. The level of the Oar2, which had two destruction-box motifs recognized by APC/C, was increased in APC/C mutants. Furthermore, the defective semi-open mitosis observed in an apc2 mutant was restored by mutated oar2+. Based on these findings, we propose that APC/C regulates the dynamics of the nuclear envelope through degradation of Oar2 dependent on APC/C during the metaphase-to-anaphase transition of semi-open mitosis in Sz. japonicus.

This study has been carried out as collaboration with Dr. Ogura at Tohoku University.

Observations of nuclear envelope dynamics in WT, apc2 mutant, and apc2∆oar2 mutant. The semi-open mitosis appeared in WT was defective in apc2 mutant, but partially restored in apc2∆oar2 mutant. Green: nuclear envelope marker (Cut11-GFP), magenta: chromosomal marker (H2A-mCherry). Scale bar: 5µm.


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